Control of electric cars.



WiCnesses: John J.F-rank, W J

No; 854,730. PATENTED MAY 2a, 1907. J. J. FRANK & J. s. PEVBAR.

CONTROL OF ELECTRIC CARS. APPLICATION IILED SBPT.19, 1906.

lnvenEors:

J1 blag.

, UNITED STATES PATENT OFFICE.

JOHN J. FRANK AND JESSE s. PEVEAR, OF SCHENEOTADY, NEW YORK, AS- SIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

CONTFfQL OF ELECTRIC CARS..

I NO. 854,730.-

Patented May as, 1907.

' Application filed September is, 1906. Serial No. 335,234.

\TO all whorm zit-may concern.- I

Be it known that we, JOHN J. FRANK and JEssE S. PEVEAR, citizens of the United States, residing at Schenectad county of Schenectady, State of New ork, respectively, have invented certain new and useful Improvements in- Control of Electric Cars, of which thefollowing is a specification.

Onr invention relates 'to the control of motor-driven cars designed for operation on both alternating and direct-caurrent Such ears are ordinarily arranged fo a direct connection between the trolley an motor con-.

troller for direct-current-operation, and an inductive connection comprising a transformer between the trolle'y and motor-controller for alternating-current operation.- It is he uently desirable that the transition from irect to alternating-current connec tionsshould be made automatically when the car runs from a direct-current trolley section to an alternating-current section,- or vice versa.- For this purpose it has been, proposed heretofore to employ magnetically-actuated switches with selective means for ac--.

tuating one magnet or the other, according to the kind of current received from the trollev.

, Our invention consists in employing a small transformer for selectively controlling both switch-Operating magnets. We accomplish this b connectingthe primary of the small trans ormer in shunt to the 'motor-cir' cult, and connecting one magnet'winding in in series with the transformer secondary, but

actuates the magnet. winding in series with the transformer primary. Alternating-cur rent, on the other hand, will'actuate the magnet winding in series with the transformer secondary, while the transformer primary acts as avchoke-coil to prevent sufficient current flowing through the magnetwinding in series with it to actuate it.

Our invention will best be understood by reference to the accompan drawing, which shows diagrammatical y an arrangement of automatic-selective devices arranged in accordance with our invention.

In the drawings, A represents the trolleyconnected directly tothe trolley B and for alternating-current operation are to be con-. 'nected to the trolley inductively through the transformer D.

E represents a small step-down transformer having its primary connected between trolley and-ground in shunt to the mo' tor-circuit. Y

F represents a magnet-winding in series with theprimary of transformer E controlling acontact which, when magnet F is ener-' gized, establishes a direct connection from trolley B to switches C. p

' G represents a second magnet winding which is inseries with the secondary of trahs former E, and which controls a contact'arranged to close a circuit from-the trolley-B to ground through'the primary of transformer D. When direct-current is flowing through the-trolley-wire, magnet winding G is not ac- 'tuated, while magnet winding F is energized by a sufficiently strong current to raise its contacts, connecting the trolley -B directly to motor-controller C for direct-current operation. The contacts controlled by this magnet winding are also arranged to cut a resistance H into circuit with the magnet winding so as to reduce the current-flow after the switch-contacts have been closed. When alternating-current is flowing through the actuate it on account of the high impedance in its-circuit formed by the primary of transformer E. i

In order to prevent the possibilityof the switch F beingtactuated incase of a shortcircuiting of the primary transformer E when the trolleyis ofi an alternating-current section, or of an abnormal flow of alternatingcurrent from any other cause, ashort-cir-l cuited band I- may be placed on the core of the operating magnet of this switch. This will not affect the operation of the switch on direct-current, but will damp out any alternating flux so as to prevent its operation on alternating-current if for any reason an excessive amount of alternating-current should flow through the magnet.

We do not 'desireto limit ourselves to the particular construction and arrangement of parts here shown, but aim in the appended claims to cover all modifications which are- 1. In an electric car designed for operation.

on both alternating and direct current, a transformer in shunt to the power-circuit of the car, two magnet windings connected respectively in series with the primary and secondary windings of the transformer, and switch-contacts controlled by said windings arranged to connect the powerci.rcuit of the car for operation on direct and alternatingcurrent respectively.

2. In an electric car designed for operation on both alternating and direct-current, a current-collecting device, a motor-controller, a direct connection from said device to said controller, an inductive connection from said small transformer, a switch-contact controlled thereby in said direct-connection, a magnet winding in series wlth the secondary of the small transformer, and a switch concar, two magnet windings connected respec tively in series with the primary and secondary windings of the transformer, switch con tacts controlled by said windings arranged to connect the power-circuit of the car for operation on direct and alternating-current respectively, and a switch-contact controlled by the magnet in the primary circuit for cutting a resistance into said circuit.

In witness whereof, we have hereunto set our hands this 17th day of September, 1906.

' JOHN J. FRANK.

JESSE S. PEVEAR. Witnesses; BENJA IN B. HULL, HELEN Onronn. 

